Knitting machine



April 17, 1962 R. H. LAWSON KNITTING MACHINE l5 Sheets-Sheet 1 FiledJuly 19, 1956 F l G.

INVENTOR. YROBERT H. LAWSON a 9&6?

ATTORNEYS April 17, 1962 R. H. LAWSON 3,029,619

KNITTING MACHINE v Filed July 19, 1956 15 sheeis-sheet 2 FIG. 2. lze

INVENTORY ROBERT H. LAWSON Y B Fl 6. l5.

ATTORNEYS April 1962 R. H. LAWSON 3,029,619

KNITTING MACHINE Filed July 19, 1956 15 Sheets-Sheet 3 ZIB FIG. H.

V FILTER V 5a REDUCING 63 VALVE 9O 'TQ RELAY i 1 9| 94 INVENTOR.

:1 ROBERT H. LAWSON q .7 F G.- 3. 74 7 7 J '1 74/47 ATTORNEYS April 1962R. H. LAWSON 3,029,619

KNITTING MACHINE Filed July 19, 1956 15 Sheets-Sheet 4 FIG. T

FIG. 4.

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I INVENTOR. l8

ROBERT H. LAWSON ATTORNEYS April 1962 R. H. LAWSON 3,029,619

KNITTING MACHINE Filed July 19, 1956 15 Sheets-Sheet 5 INVENTOR. ROBERTH. LAWSON BY Ap 1962 R. H. LAWSON 3,029,619

KNITTING MACHINE Filed July 19. 1956 15 Sheets-Sheet. 6

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ATTORNEYS April 17, 1962 LAWSON KNITTING MACHINE Filed July 19, 1956 15Sheets-Sheet '7 I I- I I- INVENTOR. I ROBERT H. LAWSON ZZWQ. f

FIG. I6.

ATTORNEYS April 17, 1962 R. H. LAWSON 3,029,619 KNITTING MACHINE FiledJuly 19, 1956 15 Sheets-Sheet 8 F G. I7.

FIG. l9.

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INVENTOR.

ROBERT H LAWSON ATTORNEYS April 17, 1962 R. H. LAWSON KNITTING MACHINEl5 Sheets-Sheet 9 Filed July 19. 1956 FIG. 20.

FIG. 2|.

INVENTOR. ROBERT H. LAWSON BY ATTORNEYS April 17, 1962 H. LAWSONKNITTING MACHINE Filed July 19. 1956 15 Sheets-Sheet 10 Fl G. 22.

FIG. 23.

INVENTOR. ROBERT H. LAW BY SON aw, 1.5% m

ATTORNEYS April 17, 1962 R. H. LAWSON KNITTING MACHINE l5 Sheets-Sheet11 Filed July 19. 1956 INVENTOR. ISOBERT H. LAWSON flmb, iii

A'FTORNEYS April 17, 1962 R. H. LAWSON KNITTING MACHINE l5 Sheets-Sheet12 Filed July 19, 1956 INVENTOR. ROBERT H. LAWSON BY ATTORNEYS April 17,1962 LAWSON KNITTING MACHINE l5 SheetsSheet 13 Filed July 19. 1956 FIG.29.

INVENTOR. BgROBERT H. LAWSON JMW.

ATTORNEYS April 17, 1962 R. H. LAWSON KNITTING MACHINE 15 Shets-Sheet 14Filed July 19, 1956 F l G. 30.

I NVENTOR. BYROBERT H. LAWSON ,2 i M v K17 ATTORNEYS April 17, 1962Filed July 19. 1956 R. H. LAWSON KNITTING MACHINE 15 Sheets-Sheet 15FIG. 33

FIG. 34.

INVENTOR. I ROBERT H. LAWSON 7 ATTORNEYS "united States ate PatentedApr. 17, 1962 3,029,619 KNITTWG MACHINE Robert H. Lawson, Pawtucket,R.I., assignor to Scott dz Williams, Incorporated, Laconia, N.H., acorporation of Massachusetts Filed July 19, 1956, Ser. No. 598,829 14Claims. (Cl. 66-55) This invention relates to knitting machines and hasparticular reference to the automatic control of stitch size and isparticularly directed to machines for the knitting of sheer ladieshosiery.

Difliculties are experienced in the knitting of sheer ladies hosiery, inparticular, in that, due to variations in yarn and in the tension ofyarn fed to the needles, stitches of varying length or size areproduced. The variations in size of individual loops are minute, but dueto the fact that a ladys stocking contains a very large number ofcourses, the minute variations of individual stitch lengths arecumulative to the end that successive stockings produced on the samemachine and seemingly under identical conditions will vary greatly withthe result that, after finishing, the stockings must be carefully sortedinto pairs of approximately equal lengths. Furthermore, while theintention may be to produce stockings of particular lengths, there maybe produced undesired numbers of stockings varying so far from thedesired lengths that for a mill to fill an order an excessive number ofstockings may have to be produced, the stockings of undesired lengthsbeing then retained in hopes of filling an order requiring theirlengths.

Furthermore, the variations in stitch lengths may occur in such fashionthat groups of courses having stitches of abnormal lengths may beinterposed betweengroupsof courses having stitches of normal lengths,and the result in such cases will be the appearance of horizontalshadowy streaks which may make the stockings unacceptable.

Further, stitches may vary in size sufficiently to produce abnormalreductions or increases in stocking circumference causing the stockingto be locally too tight or too loose when worn.

The variations indicated above as of objectionable type are not to beunderstood as those which are intentionally provided for the shaping ofstockings. It is common practice to change stitch size in a smoothlycontinuous fashion in shaping ladies hosiery from the calf portions intothe ankle portions. programmed by the controlling mechanism of theknitting machine. The objectionable variations here under. discussionare those which normally occur beyond intentional control.

In the patent to Vernon Thomas Stack, No. 2,685,786,

dated August 10, 1954, there is disclosed mechanism in a knittingmachine for the automatic control of stitch lengths having as its objectthe prevention of shadow streaks or rings, the production of properstocking diam.- eters, and the attainment of stockings of desiredoverall lengths. In accordance with the mechanism of said Stack patent,there is provided detection of variations of lengths of stitches as thestitches. are being formed, with provision for correction of stitchlengths so as to avoid the cumulativeoccurrence of stitches in largegroups of successive courses which would lead to the objectionableresults above discussed. In brief, in accordance with the said patent,the positions of sinkers are detected to give rise to signals indicativeof variations of stitch lengths from normal, and the signals thusproduced control through reversible electric motor means devices whichchange the relative positions of the stitch drawing needle cams and theledges of sinkers over which the stitches are drawn. Themechanism soshown allows for the intentional variations of stitch length incidentalto the Such variations are definitely trol. Furthermore, from apractical standpoint, a single type of pneumatic mechanism may beprovided for all localities, domestic and foreign since, except for adriving motor for the air supply, it is independent of the local powersupply which may vary from place to place in voltage and frequency andwould necessitate the pro vision of wholly different electrical systemsfor various places. Due to the relatively slow and smooth action of thepneumatic control provided, sudden variations in stitch lengths or sizesare prevented, and this is highly desirable since any sudden change institch length will be noticeable as a streak or mark in the fabric.Desirably the corrective actions should be slow so that in successivecourses, even though a corrective action is taking place, there will beno change in stitch length which will be apparent to the eye. However,provision is made in accordance with the invention for quick changes institch length where that is desired as in transitions from the welt tothe shadow welt or from the shadow welt to the leg.

Further objects of the invention relate to the attainment of stitchcontrol in various fashions which may be individually most desirable forparticular purposes in conjunction with special operations involved inthe knitting. In accordance-with the invention the stitch lengthslengths are changed by various types of manipulations of the yarn at thetime that stitches are drawn.

The foregoing and other objects particularly relating to details willbecome apparent from the following description read in conjunction withthe accompany drawings in which: I

FIGURE 1 is an elevation, partly in section, showing in particularcertain conventional element-s of the type of knitting machine to whichthe invention maybe applied;

FIGURE 2 is a fragmentary elevation showing pneumatic elements involvedin changing the height of a needle cylinder;

FIGURE 3 is a diagram illustrating the connections of a preferred typeof pneumatic system;

FIGURE 4 is a plan view of a suitable type of pneumatic relay utilizedin carrying out the invention;

FIGURE 5 is a vertical section taken on the plane indicated at 5-5 inFIGURE 4;

FIGURE 6 is an enlarged vertical section taken on the broken surfaceindicated -66 in FIGURE 4;

FIGURE 7 is'a vertical section taken on the plane indicated at 77 inFIGURE 4;

FIGURE 8 is a fragmentary plan view showing in particular the detectingmeans for abnormal stitch length;

FIGURE 9 is a perspective view showing the details of the detector;

FIGURE 9A is an exploded view showing various parts of. FIGURE 9 andexplanatory of their assembly;

FIGURE 10 is a further perspective view showing details of the detector;V

FIGUREII is a fragmentary elevation showing certain elementsparticularly involved in the fashioning control of, the stockingformation;

FIGURES 12 and 13 are fragmentary elevations, partly in section, showingcertain details of the controlling mechanism;

FIGURE 14 is a sectional plan view showing details of the mechanismillustrated in the upper portion of FIGURE 2;

FIGURE 15 is an elevation of the same;

FIGURE 16 is a fragmentary plan view of an alternative stitch controlarrangement involving control of the penetration of the sinkers betweenthe needles;

FIGURE 17 is a fragmentary elevation, partly in section, of a portion ofthe mechanism shown in FIGURE 16;

FIGURE 18 is a fragmentary elevation of a portion of the mechanism shownin FIGURE 16;

FIGURE 19 is a sectional view showing, in particular,

7 a type of sinker which may be used for stitch control;

FIGURE 20 is a fragmentary plan view showing an alternative mechanismfor producing the results secured v by the mechanism of FIGURE 16;

FIGURE 21 is an elevation, partly in section, of the mechanism shown inFIGURE 20;

FIGURE 22 is a fragmentary elevation showing mechanism for securingcontrolof stitch length by shift of position of the sinker cap;

FIGURE 23 is an elevation looking at the right of FIGURE 22;

FIGURE 24 is a perspective view illustrating the control of stitchlength by variation of position of the boxing-in cam associated with aforward stitch cam;

FIGURE 25 is a perspective view showing operating mechanism for thearrangement illustrated in FIGURE 24;

FIGURE 26 is an elevation with parts broken away, showing means forstitch length adjustment involving control of a takeup;

FIGURE 27 is an elevation looking in the direction of the arrows fromthe plane indicated at 2727 in FIGURE 26;

FIGURE 28 is a section taken on the broken surface indicated at 28-28 inFIGURE 26;

FIGURE 29 is a fragmentary elevation illustrating a 'valve controlprovided in the machine;

FIGURE 30 is a diagrammatic elevation showing certain air controlsinvolved in the machine;

FIGURE 31 is a fragmentary elevation showing valve operating meanscontrolled in accordance with operation of the machine;

FIGURE 32is a sectional view of the same; 7

FIGURE 33 is a fragmentary elevation showing certain special stitchlength control means; and

FIGURE 34 is a fragmentary detail of the same.

As noted above, the invention is particularly applicable to knittingmachines for the production of ladies sheer hosiery wherein the matterof stitch control is particularly important, though it will be evidentthat the invention is more broadly applicable to knitting machinesgenerally.

For purposes of illustration, the invention will be described as appliedto a machine of the type arranged to knit ladies sheer hosiery, themachine which will specifically be referred to being of the typedisclosed in my Patents No. 2,625,026, dated January 13, 1953, and No.2,709,352, dated May 31, 1955. Suchamachine, certain parts of which areindicatedin FIGURE 1, comprises a slotted needle cylinder 2 associatedwith which is the nonrotating but axially movable cylinder raising tube4 which is vertically moved for the purpos'e of control of stitchlength. Heretofore such a tube has been raised intermittently to controlchanges in stitc'h'leugth as between major parts of the completestocking and in particular where yarn changes have been effected, andalso for the gradual control of stitch length toproduce properfashioning of a stocking from the calf into the ankle. The adjustment of'stitchlength'in this fashion-is well known and is the result ofchanging the vertical height relation- 4 ship between the ledges of thesinkers 8, over which the stitches are drawn by the needles 6, withrespect to the level of the cams (not shown) which are at a'generallyfixed height and control the needle movements. In accordance with oneform of the present invention, the tube 4 is additionally controlled forthe correction of stitch lengths. The machine is illustrated ascomprising also the dial 10 which carries transfer elements 12 for theproduction of turned welts. Also indicated is a grab takeup 14 of thetype described in detail in my prior patents, which takeup makespossible the maintenance of proper tension during the knitting ofstockings which are individually and separately knit, each being startedon bare needles. In the remaining portion of the description hereinthere will be referred to only those elements which are intimatelyconcerned with the invention herein involved, it being understood thatthe knitting machine is otherwise of conventional type arranged to knitcomplete stocks including heels and toes.

Reference may first be made to a pneumatic relay shown in FIGURES 4 to7, inclusive, two of such relays being used in the various pneumaticcontrol systems hereinafter referred to. The relay comprises amulti-part housing 16 which provides various air connections andchambers and contains operating valve means. 'The housing provides anair supply passage 18 which communicates through a passage 20 with achamber 22. The passage 18 also communicates through a restrictedorifice 24- with a passage 26 which at one end 28 is arranged to beconnected to a nozzle as will be hereafter described and at its otherend through extension 30' to a chamber '32 a portion of the lower wallof which is provided by a flexible diaphragm 34. The diaphragm 34carries a conical valve member 36 which cooperates with a conical seatportion 38 of a passage 39 which connects the space 40 beneath thediaphragm 34 with the chamber 22. The valve member 36 is provided a stem42 of smaller diameter than the passage 39 which is arranged to engageand press downwardly a ball 44 which acts as a valve member to seat inthe lower end of the passage 39 to close the passage, the ball 44 beingurged upwardly by a light leaf spring 46. Passages 48 and 50 furnishcommunication between the space 40 and the atmosphere. Communicatingwith and extending laterally from the passage 39, is a passage 52 which,through its extensions 54 and 56 provides a controlled air outlet.

As will hereafter appear, a nozzle connected to the end 28 of passage 26is controlled by a movable bafile which, by impeding the escape of airto the atmosphere produces, in conjunction with the fixed orifice 24, avariable pressure condition in the connection 30 and the chamber 32. Asthe pressure in this chamber increases, the valve member 36 is moved bydiaphragm 34 toward a position closing the upper end of passage 3? andunseating the ball 44 from the lower end of this passage so thatcommunication is afforded between the chamber 22, which receives thesupply air, and the air outlet at 56. On the other hand, if the flow ofair from 28 is relatively unimpeded by movement of the baflle away fromthe corresponding nozzle, the pressure in chamber 32 is reduced due tothe resistance to flow imposed by the orifice at 24, and the diaphragm34 is raised by the action of spring 46 which seats the ball 44 andraises the valve member 36 so that the passage 39 is put incommunication with the atmosphere through the space 40 and the ventingpassages 48'and 50. The result is that, when the valve member 36 is infully opened position, the outlet 56 is connected to the atmosphere. Inthis fashion a'rclay action is secured providing either the supplypressure or atmospheric pressure at the outlet 56 in dependence upon theposition of a bafflle associated with a nozzle connected to the end 28of passage 26. 'Relays of this type are well known in industrial uses,and details of its operation need not be described. It will suffice forthe present instance to state that the relay is capable of providing avery large pressure dilference under control of minute movements of thebaffle referred to.

FIGURE 3 shows a typical diagram of a pneumatic system incorporatingrelays of the type just described which may be used for stitch controlpurposes in the various arrangements hereafter discussed. Air issupplied at suitable high pressure at 58 through a filter 60 to areducing valve 62 adjustable by means of a knob 61 so as to provide thedesired input pressure to the relays 64 and 66, through a valve 63which, as shown in FIGURE 29 is controlled through an arm 65 which isconnected by link 67 to an extension of the conventional lever 69activated by the pattern chain 71 to enable the usual pawl 73 to engagethe drum ratchet wheel 75. Reducing valves are well known which willmaintain substantially constant output pressure for large fluctuationsof input pressure and such valves are desirably used in a mill where thesupply pressure may fluctuate considerably in view of intermittent usesof large amounts of air for other purposes associated with a number ofknitting machines. The control connections 68 and 70 for the relays,corresponding to connections to the passage 26 at 28 of the relayalready described, terminate in nozzles 72 and 74 with which cooperatebafiles 76 and 78 arranged to control the outflow of air from thenozzles. While a pair of battles are shown herein it has been found thatequally satisfactory results may be obtained by one bafile operatingbetween directly opposed nozzles. However, the principle of control ofthe double bafiles shown herein apply to control of the single baffle.The relay 64 is shown as having its output connected at 80 to anaccumulator 82 in the form of a tank containing oil. The oil-containingspace of this accumulator 82 is connected to one end of the; cylinder 84through a connection 86 controlled by an adjustable valve 88. Thecylinder 84 contains a piston 92 to. which is secured -a piston rod 84from which mechanical power is derived. The output of the relay 66 isconnected at 9! through a filter 91 to the side of the piston oppositethat supplied through connection 86. Filter 91 is so arranged that anyliquid leaking past piston 92 will be prevented from entering relay 66.Considering specifically the arrangement shown in FIGURE 3 (which may bereplaced by numerous pneumatic arrangements known to the art), if thebafile 76 approaches more closely to the nozzle 72, pressure in therelay 64 will 'be built up above the diaphragm 34 thereof providingpressure air from the supply through the connection .88 to displace oilfrom the accumulator 82 to drive the piston 92 downwardly. The valve 88is desirable since, by partial closure of this valve, the oil flow, dueto its viscosity, may be slowed down to provide a smooth slow movementof the piston 92 rather than a rapid movement. Slow movement isdesirable not only to prevent hunting but further in the case of stitchlength adjustment since a rapid adjustment of stitch length might resultin such a sharp change in the stitches that a visible shadow ring orother marking might result. Desirably the change is a gradual one sothat substantial change will not occur except over a knitting period ofseveral courses. As will be evident, if the battle 78 is moved towardits nozzle and the baflie 76 simultaneously moved away from its nozzle areverse action will occur involving upward movement of the piston 92 andreverse flow of oil through connection 86 and valve 88 from the cylinderto the accumulator. As will appear hereafter the baflles correspondingto 76 and "78 are moved oppositely with respect to their nozzles so thatreverse movements of the piston 92 correspondingly occur to effectcorrective actions in one of the fashions which will be described. Itmay be noted that the pneumatic control may be of one of the moreelaborate types well known in the process control art to achieve finecontrol with avoidance of hunting, though the simple control describedhas been found highly satisfactory for stitch control purposes.

It is desirable in machines of the type herein disclosed to shut off themain air supply when the machine stops due to the operation of the stopmotion or for other cause such as failure of the main power supply ormanual stopping of said machine. Heretofore, air used in conjunctionwith a grab take-up has been shut ofi, when the machine was manuallystopped, to prevent waste of arr.

In the present instance, where the stitch size is servo controlled thrua detector cam 150, whose control action is hereafter described,stopping of the machine with the air on may cause the piston 92 totravel to its eX- treme in one direction or the other depending uponwhich of the relays 64- or 66 happens to be activated when the machinestops, it the comparatively simple system herein described is used. Anextreme stitch such as would be obtained when the piston 92 goes to oneextreme or the other in its cylinder 84- would cause difiiculty inrestarting the machine due to the stitch being too tight or loose and ofcourse would in any case result in loss of the stocking.

One example of a control for shutting off the air when the machine stopsfor any reason is shown in FIGURES 30, 31 and 32. This control consistsof housings 500 and 5822 held together by screws 504. A shaft 506carrying a bladed rotor 508 passes thru bearings 510 and 512respectively in housings 500 and 502. These bearings carry seals such asmay be provided by 0 rings to prevent lubricant inside housings Stilland 502 from passing out between rotating shaft 506 and bearing 510 and512. Shaft 586 also carries fastened thereto a gear 514 which mesheswith the bull gear 516 with which machines of the type here disclosedare equipped, being used to drive a quadrant gear (not shown) thru aconnecting rod (not shown) to oscillate the cylinder during the makingof heels and toes. Gear 516 always travels in one direction regardlessof whether the needles are revolving or reciprocating.

Bla ded rotor 508 is made integral with shaft 506 as by brazing and assaid shaft 506 is caused to rotate the rotor 508 revolves insidehousings 580 and 502. Housings 580 and 502 are provided with cavitiesseparated by walls and the latter approach the blades of rotor 508,being separated therefrom by a very small clearance being measured inone or two thousandths of an inch. Housings 500 and 502 with the rotor508 therein are completely filled with a grease that will substantiallymaintain its density over a wide heat range, for example, a siliconegrease. The movement of the grease caused by the angle blades on rotor508 from cavities in one of the housings 56-8 and 502 to the cavities inthe other housing causes a variable torque to be applied to saidhousings dependent on the speed with which rotor 508 is turned.

This device has been so designed and the gear ratio between 516 and 514is such that when the machine is run at its slowest normal speedsufiicient torque is built up in housings 506 and 502 to cause them torevolve clockwise as seen in FIGURE 31 against the tension applied byspring 518 thus opening valve 524) through link 522. Spring 518 actsnormally to close valve 520 immediately upon stopping of the machinewith-consequent loss of torque to housings 500 and 502. Spring 518through link 522 revolves said housings 560 and 582 anti-clockwise(FIGURE 31) lifting the lever of valve 520 and closing it.

Air is supplied to valve 520 immediately following its passage throughfilter 60 and before entering an air controlled pilot operated valve 524located between filter 6i) and reducing valve 62. Thus air is availableto valve 520 regardless of whether valve 524 is open or closed but airis available to the grab take-up and the pneumatic stitch control onlywhen valve 524 is open. Running of the machine causes housings 5G8 and582 to revolve clockwise as explained above overcoming the tension inspring 518 and opening valve 520 thus supplying air to the pilot side ofvalve 524 causing the opening of said I cylinder 84 and valve 524 andthe consequent supplying of air to various parts of the machine asrequired. Stopping of the machine or even abnormal slowing down of themachine releases the torque built up in housings Silt) and 592 allowingspring 513 to return to a position where thru connection 522 they willcause valve 520 to close, which in turn shuts off main valve 524.

Changing the density of grease in housings 590 and 502, changing therelative diameters of these housings and rotor 508 and also changing thetension in spring 518 will cause opening and closing of valve 521 tooccur at different speeds of the knitting machine as may be desired.

Referring now particularly to FIGURES 2 and 8 to 15, inclusive, there isshown therein one form of the invention'in which control of the lengthof stitches is effected by adjustment of the height of the needlecylinder relative to the needle operating cams. changes the height ofthe sinker ledges relative to the needle wave thereby providingvariations in the loops drawn by the needles over the sinker ledges.

The physical arrangement of the accumulator 82 and their associatedparts, diagrammed in FIGURE 3, is shown in FIGURE 2, the accumulator andcylinder being secured to a leg of the knitting machine as illustratedtherein. The piston rod 94 has connected to it a plate 96 which througha link 98 is connected to operate the devices controlling the height ofthe needle cylinder through adjustment of the tube 4. A fixed bracket100 has mounted therein a pair of aligned pivot pins 102 and 104 onwhich there is pivotally mounted a stirrup 105. A shaft 198 mounted inthis stirrup supports for oscillation a member 119 the circumference ofwhich is eccentric to the axis of the shaft 103 and mounts a ballbearing 112 the purpose of which is to reduce friction. Engageable withthe outer race of this ball bearing is an adjustable screw 11% threadedin a bracket 116 secured totube 4 and provided with a graduated head 118the position of which may be read against an index pointer 12%. Securedto the member 110 is an arm 122 which has a pivotal connection with thelink 98. An arm 124 secured to the stirrup 166 is provided with anadjustable screw 126 arranged to abut during certain phases of operationa fixed extension 128 of the bracket 1% under the action of a spring14%, thereby limiting swing of the stirrup in a cylinder-lowerdirection. The arm 124 at its free end is provided with a pair ofadjustable screws 130 and 13-2 which are arranged to be engaged,respectively, by the cams 134 and 136 carried by the fashioning drum138. If desired, adjustable screw 126 may be placed in line with screws130 and 132 to operate on a third cam carried by the fashion drum 138.As will further appear hereafter, the motions involved are thefollowing:

Assuming the pivot at the outer end of arm 122 in fixed position, i.e.,the link 98 stationary, the stirrup 106 may be rocked by the actions ofcams 134'and 136 thereby eifecting movement bodily of the shaft 108 andmember 110 and the ball bearing 112 which it carries. Pivotal movementin such case is about the axis of the pins 102 and 104-. On the otherhand, if the stirrup 1% is in a rest position with the screw 126engaging extension 128 or with one of the pins 136 or 132 engaging itscorresponding cam, the movement of arm 122 by link 28 will effectrocking of the eccentric member 114 about the axis of shaft 108 therebyproducing rise or fall of the ball bearing 112 to effect correspondingrise or fall of the tube 4 and needle cylinder. The reasons for thesemotions will be later described.

. The shaft 142 of the main pattern drum of the machine, which isconventional and not shown, has secured to it, by location on itsdriving gearga cam 144 which is arranged to operate on a plunger 146which is connected to a link 145. This ser es for activation or This, ineifech lateral extension deactivation of the pneumatic controlling meansas will appear hereafter.

A detector cam 15% which rides on the butts of sinkers S is pivoted at152 in a slot in the sinker cap. Engageable with this detector cam isthe depending finger 154 of a lever 156 which is pivoted on a pin 158fixed in a slide 160 which is slidable toward and from the axis of theneedle cylinder in a fixed bracket 162. Two other levers 164 and 1-66are also mounted to pivot on the pin 15% and carry respectively thebattles 168 and 170 which correspond, respectively, to the bafiles 76and 78 diagrammed in FIGURE 3. Lever 156 is provided with a 172 inwhichis threaded an adjustable screw 174 the lower end of which isarranged to bear upon the baflle 170. A spring 176 between the battleand screw urge them into engagement. An extension 17% of lever 16-4 hasthreaded therein an adjustable screw 180 which bears upon the end oflever 156. A spring 182 reacting between the screw 180 and a fixedelement serves normally to maintain the engagement between screw 180 andthe lever 156. The baffles 168 and 170 cooperate, respectively, with thenozzles 184 and 186 corresponding, respectively, to the nozzles 72 and'74 in FIGURE 3, and opening, respectively, upwardly and downwardly. Aswill be evident from the prior description of FIGURE 3, when the baffle170 closes 01f flow of air from nozzle'186' there will be built uppressure beneath the piston 92 to effect rise of the piston andconsequent rise of the tube 4. On the other hand, if bafiie 168 closesnozzlelSd, the piston will be moved downwardly and, correspondingly, thetube 4 will be moved downwardly. The use of the eccentric member 110provides for only slight movements of the tube 4 for very considerablemovement oithe lever arm 122 and the piston rod 94. For example, in atypical case, the tube a is moved about 0.035 inch for a piston movementof 4 inches.

A wedge lsfi is arranged for vertical movement in the bracket 162 and ismoved by a heavy Bowden wire 190 which extends through a sheath 192 andis connected to a lever 194. The slide 160 is provided at its outer endwith a plate 196 in which is threaded an adjustable screw 198 whichrides on the wedge 183. A spring 200 urges the slide 169 toward the axisof the needle cylinder. A lever 202 which is pivoted to the frame at 204is connected at 206 to an adjustable extension 208 of the link 148. Theouter end of the lever 202 engages the plate 196 so that, as link 148 israised through the action of cam 144 the slide 16% is moved outwardlyfrom the needle cylinder. Secured to the upper end of the link 148 is ablock 210 which is provided with a wire arm 212 having a portion 214underlying the battle 168. The arrangement is such that as the link 148is raised the batlle 168 is raised away from its nozzle 184.

The lever 19 4 to which reference has already been made is pivotedat-216 to a bracket 218 and is provided with three aligned adjustablescrews 220 only one of which appears in FIGURE 11. These screws arerespectively adapted to be engaged by earns 2.22, 224 and 226 carried bythe fashioning drum 138 which is journalled on the shaft 142 as shown inFIGURE 12. The fashioning drum is provided with ratchet teeth 228extending approximately two-thirds of the way about its circumferenceand arranged to be acted upon in usual fashion by a pawl 229 whichreciprocates during operation of the machine. An adjustable screw 230 ismounted in the lever 194 and is arranged to limit its counterclockwisemovement tinder the action of spring 234 by abutment with the lateralextension 232 of the bracket 218. The cam 222 is contacted by lip 233 toadvance drum 138 where teeth 228 are omitted. Said lip 238 is providedon a plate 232 secured to the shaft 142. A spring brake 24G holds thefashioning drum 138 in position against accidental displacement and alsoserves to restrain overrun of this drum.

The operation of the arrangement just described is as follows:

During the makeup at the start of the stocking the height of the needlecylinder is controlled in the usual manner from the main cam drum of themachine. At this time the piston 92 will be in the position resultingfrom the formation of the angle of a previous stocking, and will he,therefore, in a lowered position corresponding to automatic control oftight stitches. It may be here noted that the automatic control of theneedle cylinder through the action of ball bearing 112 on screw 114 doesnot interfere with raising of the cylinder by conventional control fromthe main cam drum of the machine, though it would interfere with suchlowering of the cylinder. However, if it is desirable in the making ofcertain stockings to still further lower the cylinder, for the heel andtoe for example, beyond the lowest position achieved by such cylinder inthe making of the ankle then this can be arranged by having screw 1%ride on a third cam on the fashion drum instead of against abutment 128.The follower 146 is at this time raised by cam 144- and, consequently,the slide 160 is in retracted posiiton with the result that balfie 179is clear of the nozzle 186. At the same time the end 214 of wire 212holds the baflie 168 raised from nozzle 184. The air system isaccordingly deactivated, so that the piston remains as stated. Ifdesired, the air system may also be deactivated by closure of an airvalve from the main cam drum, though such deactivation would serve nopurpose except to prevent waste of air through the nozzles.

During the fashioning of the ankle of the preceding stocking the pawl229 will have advanced the ratchet 228 until, following the engagementof the trailing tooth, it will be riding idly upon the portion of thedrum 138 which has no teeth. During the formation of the heel, foot, andtoe of the preceding stocking and the initial part of the makeup of thenew stock the shaft 142 will have stepped about, but will not havecaused lip 238 to engage the portion 236 of cam 222. During the lastdrum move involved in the makeup, the shaft 142 will have a step so that238 will engage 236 to move the cam 222 beneath the corresponding screw220 to position the lever 194 and the wedge 13% properly for the makingof welt stitches. At the same time, cam 134 which also is attached todrum 138 engages screw 130 to raise ball bearing 112 to a position alittle short of that which, with lever 122 lowered would produce properwelt stitches. Desirably at this same time the usual quality controlcams are moved to effect movement of the needle cylinder to a heightwhich would correspond to the production of welt stitches slightlytighter than desired.

Also at this same time the rod 146 is released by the cam 144. Theresult is that bafile i168 is released and the slide 166* moves inwardlyto engage follower screw 198 with the wedge 188 occupying now a positioncorresponding to the production of proper size welt stitches. The sinkerdetector cam 156 will now be in a position slightly outwardly of thatdesired in view of the formation of welt stitches tighter than desired,and consequently lever 156 will be rocked counterclockwise to engagebaflle 70 with nozzle 1%. The piston will accordingly be caused to riseas already described to move the lever 122 in the direction to effect aproper cylinder level. As slackening of stitches results, the needlecylinder being raised by the automatic control through lever 122 abovethe position previously determined by the conventional stitch qualitycontrol cam on the main cam drum, the sinkers are moved inwardly underthe action of detector cam 150 through the action of spring 182,effecting removal of baffle 170 from nozzle 186, thereby arresting thepiston movement. Control in this fashion is typically attained withinone or two courses after the pneumatic stitch control device isactivated, though the rapidity of action of this control is adjustablethrough control of valve 88. i

During the knitting of the welt automatic stitch length controlcontinues. If the stitches become too tight, the detector cam 15% ismoved outwardly by the sinkers resulting in closure of nozzle 136 bybaffle 170 and slight readjustment of the needle cylinder in an upwarddirection. On the other hand, if the stitches become too loose, thefollower cam 1% moves inwardly with the result that nozzle 184 is closedby baffle E68 resulting in slight downward adjustment of the needlecylinder. Desirably, the automatic adjustment is relatively slow, sothat there is no radical change in size of the stitches such as wouldproduce an appearance of rings in the fabric. Due to the positioning ofstirrup 106 by cam 134 the ball bearing was positioned to a height suchthat the piston in the pneumatic cylinder need only travel an amountequivalent (though in the opposite direction) to the distance it movedfor fashioning to make welt stitches of the desired length as called forby the automatic control from the sinkers through cam 150. But even ifcam 134 were omitted, the stitches would be controlled as to length inaccordance with the setting of wedge 188, lever 122 operating then in ahigher portion of its range of movement. Cam 134- is actually providedfor a different purpose as will be shortly discussed. It may be notedthat the stitch adjustment is not an adjustment of abnormal stitchesalready drawn, but rather is in the nature of a compensating adjustmentof subsequently formed stitches both to balance the abnormal stitchesand secure stitches of more proper length. This action of compensatingfor stitches of abnormal size is important throughout the formation ofthe circular knit parts of a stocking, and particularly the leg, to besure of proper overall size of the stockings produced.

Continuing the description of the operation, following the transfer ofthe welt the-drum 138 is advanced by engagement of lip 2.38 with cam end236 to release cam 222 from its follower screw and to bring cam 224 intoengagement with a second one of the screws 22!) to position the wedge188 properly for the formation of shadow welt stitches. The action is,of course, to reposition the slide so that the automatic control may beeffected from a different predetermined value of stitch length.Automatic control would then take place as before, and the screw 22thwhich follows cam 224 may be adjusted to secure the desired stitchlength. It may be here remarked that adjustment of screw 1% is primarilyto effect a common adjustment of all stitches while the relativepositions of the screws 229 efiect relative adjustments to the stitchesin the different areas of the stocking.

There is, however, another matter involved in the transition from thewelt to the shadow welt. As has been above mentioned, it is notdesirable to have the automatic stitch length control operate rapidlysince otherwise there may be produced horizontal streaks in thestockings. But Without the provision of special control, this wouldresult in an objectionable condition in the transition between the weltand shadow welt (and also between the shadow welt and leg). Ordinarilythe shadow welt stitches are shorter than those desired for the welt,and if only the automatic control was involved there would be a slowvariation of stitch length which would be objectionable in appearance.It was previously remarked that while the needle cylinder could bequickly moved from the main cam drum it could not be quickly moved froma position determined by the ball bearing 112 if the sole control ofthis ball hearing was from the lever 122 through its pneumatic drive.Accordingly, to produce a quick drop of the needle cylinder the earn134- is caused to ride from beneath follower 139 so that the stirrup 106will drop to a position determined by engagement of follower 132 withcam 135. This transition occurs in the step of the drum Z38 previouslymentioned in going into the formation of shadow welt stitches. Theneedle cylinder is thus dropped abruptly even though the lever 122 mayhave no appreciable movement during such drop. The drop of the needlecylinder is made to the

